Aiming sights for weapons have a wide variety of physical configurations. One that is frequently used for gun sights, or many other aiming devices, comprises a pair of open sights, such as U-shaped sights having a horizontal opening of substantial width. This sight is located proximal to the weapon user. The open width of the U-shaped sight must be sufficient to permit sighting of the single distal sight on the weapon. In this case, the user attempts to locate the single distal sight superimposed on the putative target, and simultaneously align that single sight on a horizontal line midway between the two proximal sights. Other sight configurations have been proposed (see, e.g., U.S. Pat. No. 3,698,092). In all sight configurations it is desired to have each sight easily visible under all lighting conditions.
Various types of aiming sights for daylight operation of projectile type weapons are known. Several patents pertaining to such sights include U.S. Pat. Nos. 3,568,323; 3,579,830; 3,822,479; 4,177,572; 4,495,705; 4,819,611; 4,928,394; 5,001,837; 5,094,002; 5,121,462; 5,121,462; 5,168,540; 5,168,631; 5,201,123; and 5,442,861. More recently, there has been interest in the use of plastic optical fibers in such sights. These plastic optical fibers can incorporate a dye which absorbs ambient light and then emits fluorescent light. A fraction of the fluorescent light which is emitted can then be channeled by the plastic optical fiber and exit from the end of the fiber pointing toward the user of the weapon.
Similarly, there has been a variety of sights used for nighttime self-illumination of sights. Several patents pertaining to such sights include U.S. Pat. Nos. 3,641,676; 3,698,092; 3,701,900; 3,706,543; 3,834,035; 3,908,055; 3,914,873; 4,020,203; 4,695,159; 5,065,519; and 5,359,800.
These sights frequently use one or more radioluminous light sources located, for example, in a recess, so as to expose the user of the weapon to the luminous light but conceal the luminous light from other points of view. These radioluminous light sources have frequently used material compositions comprising tritium. Other light sources have also been used such as electrically powered light emitting diodes, chemofluorescent light sources, and long lived phosphorescent light sources.
There have been attempts to produce aiming sights which can operate in both day and night lighting conditions. Most notable is the approach of Fisher, disclosed in U.S. Pat. No. 5,359,800. Fisher discloses a sight having a radioluminescent light source which is surrounded by a light reflective paint. During the day, the paint reflects light to the user so as to provide the appearance of a colored light ring. During the night the radioluminescent light source produces light which is directed toward the user. However, the daylight reflected light from the Fisher sight can be quite low. In fact, in medium to low light level conditions, the reflected light can be inadequate. Furthermore, the radioluminescent light can be too low relative to the ambient light level to provide adequate light for the user of the weapon.
It is a purpose of the present invention to describe a sighting device which can provide adequate light for a weapon user under all lighting conditions.
The subject invention pertains to a method of sighting and a sighting apparatus which can operate during the day and/or night. In a preferred embodiment, the subject sight will be able to operate in essentially any lighting conditions. The subject invention also relates to sighting systems incorporating a plurality of individual sights in a variety of physical configurations.
In accordance with the subject invention, an illumination source can be aligned along the axis of a fluorescent optical fiber and optically connected thereto. The unique design of the fluorescent fiber is such as to permit essentially total light transmission from the illumination source through the fiber towards the weapon user, and at the same time emit adequate fluorescent light intensity from its end towards the user even under adverse lighting conditions. The subject invention also pertains to various embodiments of a fluorescent fiber which can be utilized in this way.